<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>el:挂载点</title>
</head>
<body id="body">
    {{ message }}
    <h2 id="app" class="app">
        {{ message }}
        <span>{{ message }}</span>
    </h2>
    <!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
    var app = new Vue({
       //el:"#app",
        //el:".app",
        //el:"div",
        el:"body",
        data:{
            message:"黑马程序员"
        }
    })
</script>
</body>
</html>